Array Slicing

Basic Slicing with Offset and Length

${arr[@]:offset:length} extracts a sub-list of elements starting at index offset, taking up to length elements from there. This avoids manually looping and building a new array by hand.

Example: Basic Slicing with Offset and Length

#!/bin/bash
letters=(a b c d e f)
slice=("${letters[@]:1:3}")
echo "Slice: ${slice[@]}"

Omitting the Length

Leaving out the length argument, ${arr[@]:offset}, takes every element from offset through the end of the array. This is a convenient way to say 'everything after this point'.

Example: Omitting the Length

#!/bin/bash
numbers=(10 20 30 40 50)
rest=("${numbers[@]:2}")
echo "From index 2 onward: ${rest[@]}"

Negative Offsets Count From the End

A negative offset counts backward from the end of the array, but it must be written with a space (or wrapped in parentheses) before the minus sign, like ${arr[@]: -2}, otherwise Bash parses it as the ${var:-default} expansion instead of a slice.

Warning: ${items[@]:-2} (no space) means something completely different -- it's the default-value expansion, not a slice.

Example: Negative Offsets Count From the End

#!/bin/bash
items=(one two three four five)
last_two=("${items[@]: -2}")
echo "Last two items: ${last_two[@]}"

Slicing Strings the Same Way

The identical :offset:length syntax also works directly on plain string variables, extracting a substring by character position instead of array element position. This consistency makes slicing syntax easy to remember across both arrays and strings.

Example: Slicing Strings the Same Way

#!/bin/bash
text="Hello, World!"
echo "Substring: ${text:7:5}"